1. Field of the Invention
The present invention concerns improved methods and devices for construction of permanent perimeter foundations and anchorage therefor, especially for pre-situated structures, such as mobile homes and modular housing.
The present invention particularly concerns a pre-hung corrugated steel wall panel that is cast-in-place with footing concrete thus creating a structural foundation wall. The relevant components and methods allowing this new use of the common corrugated panel material are also disclosed, as are embodiments of this foundation wall providing thermal efficiency, particularly for metal structures.
2. Description of Prior Art
2.1 General Background
Conventionally, perimeter foundation walls are built from the bottom up. After a site is prepared, the geometry for that foundation is typically created by careful measurement and the setting-up of strings which each define a face of the foundation. Then the foundation walls are built as close as practical to these string lines, while attention is paid to level and plumb, et cetera.
A procedure such as this is typically followed for a perimeter foundation of a prefabricated modular structure, which must subsequently be positioned upon that foundation. Unless a crane of suitable capacity is available, setting the modular unit(s) upon the finished foundation involves a difficult process of sliding, adjusting, lowering, fitting, blocking, and attaching. Quite often the foundation will have enough deviation in accuracy to cause problem with fit of the modular unit(s).
The use of corrugated panels, by themselves, as bearing walls is a practice known to be utilized in light steel building construction to a limited degree. Corrugated steel sheet-piles are common in earth-work as temporary or permanent load-bearing and retaining walls.
2.2 Specific Prior Art
This inventor's research has uncovered only one patent involving cast-in-situ bearing-panel foundation walls. U.S. Pat. No. 3,820,295, by M. Folley, June 1974, discloses the use of corrugated steel foundation walls cast into concrete, as part of a system for constructing a corrugated panel building. Inverted "T" sections of corrugated panels are set into a trench, then partially cast into concrete, and finally remain as foundation walls. These panel "T" assemblies are built of perpendicular (horizontal) panel elements attached along the bottom edge of the wall (vertical) panel elements with continuous gusset elements each side, by welding upon each flute of each corrugated element to each flange of both continuous gussets. Multiple holes are also placed in the gussets and the horizontal corrugated panels, apparently to help allow some flow of the concrete throughout the assemblage.
The "T" panels disclosed cause considerable and unnecessary manufacturing expense and storage difficulties, while presenting an obstruction to the placement of concrete within the confines of a trench. The continuous "T" element causes difficulty in the required pre-support of the panels by adding extra weight, requiring extraordinarily accurate or over-sized footing trenches, and especially because the horizontal plane presence will catch the concrete being placed so creating a devastatingly high load upon the temporary support to the panels.
It could be assumed that the intended general construction sequence is conventional, but no disclosure is given for a method of pre-situating the panels. This aspect of that invention's foundation is the most important because the panels would have to be cast in place exactly, straightly, and precisely where required to be of any use for the continuing construction of the building above, which is of pre-fabricated elements. In addition, the complications of the "T" base require that the pre-support also remain perfectly in place while under the very high loads of concrete placement. No adjustment or tolerance of significance would be possible after the panels are cast in-situ.
The Folley patent emphasis is on the unique construction above the foundation walls. Based upon the disclosure given, that foundation method appears to have not succeeded in construction practice, let alone provide cost efficiency.